1. Field of the Invention
The invention relates in general to a method and an apparatus for determining a sound standard of a television system, and more particularly to a sound standard detecting method and an apparatus thereof capable of correctly and rapidly detecting a sound standard for an input sound signal.
2. Description of the Related Art
A current analog-modulated television system (e.g., a receiver) has to firstly determine an unknown sound standard for an input sound signal. This mechanism operates when a demodulator of the television system is initialized to provide the information for setting the demodulator. In order to prevent the normal operation of the receiver from being influenced, a sound standard determining method has to correctly and rapidly detect the sound standard for the input sound signal.
A conventional sound standard detecting method is performed in a try and error manner to detect carrier frequencies corresponding to possibly matched sound standards for the input sound signal. However, the conventional sound standard determining method is quite time-consuming and cannot satisfy the requirement of rapidly detecting the sound standard. In addition, the conventional sound standard determining method cannot correctly determine a portion of the sound standards. So, how to provide a sound standard detecting method capable of correctly and rapidly detecting the sound standard for the input sound signal is a target to be reached in the industry.